XML 34 R42.htm IDEA: XBRL DOCUMENT
v3.20.1

Fair Value Measurements - Assets and Liabilities Carried at Fair Value Measured on Recurring Basis (Details) - Fair Value, Measurements, Recurring - USD ($) | Dec. 31, 2019 | Dec. 31, 2018
--- | --- | ---
Assets |  |
Total assets at fair value | $ 1,761,363 | $ 1,572,496
Marketable Equity Securities |  |
Assets |  |
Total assets at fair value | 1,761,312 | 1,567,607
Interest Rate Cap |  |
Assets |  |
Total assets at fair value | 51 | 4,889
Level 1 |  |
Assets |  |
Total assets at fair value | 1,761,312 | 1,567,607
Level 1 | Marketable Equity Securities |  |
Assets |  |
Total assets at fair value | 1,761,312 | 1,567,607
Level 2 |  |
Assets |  |
Total assets at fair value | 51 | 4,889
Level 2 | Interest Rate Cap |  |
Assets |  |
Total assets at fair value | $ 51 | $ 4,889

X
- Definition Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258 + Details
Name: | us-gaap_AssetsFairValueDisclosure
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- References No definition available. + Details
Name: | us-gaap_AssetsFairValueDisclosureAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_FairValueByMeasurementFrequencyAxis=us-gaap_FairValueMeasurementsRecurringMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentTypeAxis=self_MarketableEquitySecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=us-gaap_InterestRateCapMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel1Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel2Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |